Postsecondary undermatch occurs when students fail to enroll at a college or university that possesses a level of selectivity their academic credentials would permit them to attend. Given the demonstrated link between selective college attendance and postsecondary and professional attainment, recent studies have attempted to examine which factors may prevent students from enrolling at appropriately competitive institutions. Using data provided by NCES's Educational Longitudinal Survey (ELS:2002/2006), this study aims to quantitatively assess whether results yielded from these studies generalize to a national level, and whether other contextual variables play a significant role. Descriptive results show that postsecondary undermatch is indeed a pervasive phenomenon, but not as widespread as previous studies have claimed; while multilevel analysis suggests that background, environment, and college-related attitudes have significant influence on the likelihood of undermatch.